U.S. patent application number 14/624531 was filed with the patent office on 2015-07-23 for apparatus and method of preparing and delivering a fluid mixture using direct proppant injection.
The applicant listed for this patent is General Electric Company. Invention is credited to Jason Paul Mortzheim, Stephen Duane Sanborn, Tiffany Elizabeth Pinard Westendorf.
Application Number | 20150204166 14/624531 |
Document ID | / |
Family ID | 53544356 |
Filed Date | 2015-07-23 |
United States Patent
Application |
20150204166 |
Kind Code |
A1 |
Sanborn; Stephen Duane ; et
al. |
July 23, 2015 |
APPARATUS AND METHOD OF PREPARING AND DELIVERING A FLUID MIXTURE
USING DIRECT PROPPANT INJECTION
Abstract
An apparatus and method for preparing and delivering a fluid
mixture. The apparatus including a high pressure differential
solids feeder assembly and a pressurized mixing apparatus. The
feeder assembly is coupled to a proppant storage vessel at ambient
pressure and receives a continuous unpressurized proppant output
flow from the proppant storage vessel. The feeder assembly is
configured to output a continuous pressurized proppant output flow
of sufficient mass to achieve continuous operation of the apparatus
in an uninterrupted episode for an individual fracture stage. The
pressurized mixing apparatus is coupled to the feeder assembly and
in fluidic communication with the continuous pressurized proppant
output flow and a continuous pressurized fracturing fluid flow. The
pressurized mixing apparatus is configured to output a continuous
flow of a pressurized fluid mixture of a sufficient volume and mass
to achieve continuous operation of the apparatus in an
uninterrupted episode for the individual fracture stage.
Inventors: |
Sanborn; Stephen Duane;
(Copake, NY) ; Mortzheim; Jason Paul;
(Gloversville, NY) ; Westendorf; Tiffany Elizabeth
Pinard; (Troy, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
53544356 |
Appl. No.: |
14/624531 |
Filed: |
February 17, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13689873 |
Nov 30, 2012 |
|
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14624531 |
|
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Current U.S.
Class: |
166/244.1 ;
166/75.11 |
Current CPC
Class: |
E21B 43/267 20130101;
E21B 21/062 20130101 |
International
Class: |
E21B 41/00 20060101
E21B041/00; E21B 43/267 20060101 E21B043/267; E21B 43/16 20060101
E21B043/16; E21B 43/25 20060101 E21B043/25 |
Claims
1. An apparatus for preparing and delivering a fluid mixture
comprising: a high pressure differential solids feeder assembly
coupled to a proppant storage vessel at an ambient pressure, the
high pressure differential solids feeder assembly including a
proppant inlet in fluidic communication with a proppant flow at the
ambient pressure, the high pressure differential solids feeder
assembly configured to output a continuous pressurized proppant
output flow of a sufficient mass to achieve continuous operation of
the apparatus in an uninterrupted episode for an individual
fracture stage, wherein the continuous pressurized proppant output
flow is output at a mixing pressure, wherein the mixing pressure is
greater than the ambient pressure; and a pressurized mixing
apparatus coupled to the high pressure differential solids feeder
assembly, the pressurized mixing apparatus including at least one
inlet in fluidic communication with the continuous pressurized
proppant output flow and a continuous pressurized fracturing fluid
flow, the pressurized mixing apparatus configured to mix the
continuous pressurized proppant output flow and the continuous
pressurized fracturing fluid flow therein and output a continuous
flow of a pressurized fluid mixture of proppant and fracturing
fluid of a sufficient volume and mass to achieve continuous
operation of the apparatus in an uninterrupted episode for the
individual fracture stage, wherein the continuous flow of the
pressurized fluid mixture of proppant and fracturing fluid is
output at or above the mixing pressure.
2. The apparatus of claim 1, further comprising: a pump assembly
coupled to the pressurized mixing chamber and configured to deliver
the continuous flow of the pressurized fluid mixture of proppant
and fracturing fluid to a downstream component at an injection
pressure, wherein the injection pressure is greater than the mixing
pressure.
3. The apparatus of claim 1, wherein the high pressure differential
solids feeder assembly is a rotary displacement pump assembly with
a consolidation section, a rotation section and a discharge
section.
4. The apparatus of claim 1, wherein the high pressure differential
solids feeder assembly is an eductor pump assembly.
5. The apparatus of claim 1, wherein the high pressure differential
solids feeder assembly is a rotary positive displacement pump
assembly.
6. The apparatus of claim 1, wherein the mixing pressure is in a
range of 200-400 psi.
7. The apparatus of claim 5, wherein the mixing pressure is
approximately 300 psi.
8. The apparatus of claim 1, wherein the injection pressure is in a
range of 5000-12,000 psi or higher.
9. The apparatus of claim 1, wherein the injection pressure is
approximately 10,000 psi.
10. The apparatus of claim 1, wherein the proppant material is one
of sand, ceramic proppant, or a mixture thereof.
11. The apparatus of claim 1, wherein the fracturing fluid is one
of liquid CO.sub.2, liquid propane or a mixture thereof.
12. An apparatus for preparing and delivering a fluid mixture
comprising: a proppant storage vessel configured to contain therein
a proppant material and output a proppant output flow at ambient
pressure; a high pressure differential solids feeder assembly
coupled to the proppant storage vessel, the high pressure
differential solids feeder assembly including a proppant inlet in
fluidic communication with the proppant output flow, the high
pressure differential solids feeder assembly configured to output a
continuous pressurized proppant output flow of a sufficient mass to
achieve continuous operation of the apparatus in an uninterrupted
episode for an individual fracture stage, wherein the continuous
pressurized proppant output flow is output at a mixing pressure,
wherein the mixing pressure is greater than the ambient pressure; a
fracturing fluid storage vessel configured to contain therein a
fracturing fluid and output a continuous pressurized fracturing
fluid output flow at a mixing pressure, wherein the fracture mixing
pressure is greater than the ambient pressure; a pressurized mixing
apparatus coupled to the high pressure differential solids feeder
assembly, the pressurized mixing apparatus including at least one
inlet in fluidic communication with the continuous pressurized
proppant output flow and the continuous pressurized fracturing
fluid flow, the pressurized mixing apparatus configured to mix the
continuous pressurized proppant output flow and the continuous
pressurized fracturing fluid flow therein and output a continuous
flow of a pressurized fluid mixture of proppant and fracturing
fluid of a sufficient volume and mass to achieve continuous
operation of the apparatus in an uninterrupted episode for the
individual fracture stage, wherein the continuous flow of the
pressurized fluid mixture of proppant and fracturing fluid is
output at or above the mixing pressure; and a pump assembly coupled
to the pressurized mixing chamber and configured to deliver the
pressurized fluid mixture therein to a downstream component at an
injection pressure, wherein the injection pressure is greater than
the mixing pressure.
13. The apparatus of claim 12, wherein the mixing pressure is in a
range of 200-400 psi.
14. The apparatus of claim 13, wherein the mixing pressure is
approximately 300 psi.
15. The apparatus of claim 12, wherein the injection pressure is in
a range of 5000-12,000 psi.
16. The apparatus of claim 12, wherein the proppant material is one
of sand, ceramic proppant, or a mixture thereof, and the fracturing
fluid is one of liquid CO.sub.2, liquid propane or a mixture
thereof.
17. The apparatus of claim 12, wherein the high pressure
differential solids feeder assembly is coupled to the proppant
storage vessel, the high pressure differential solids feeder
assembly comprising: a consolidation section configured to cause
the proppant material to compact and act as a solid mass; a
rotating section configured to increase the pressure of the
proppant material therein; and a discharge section configured to
discharge the proppant material at the increased mixing
pressure.
18. The apparatus of claim 12, wherein the high pressure
differential solids feeder assembly is an eductor pump assembly
coupled to the proppant storage vessel and the fracturing fluid
storage vessel, the eductor pump assembly comprising: a suction
chamber in fluidic communication with the proppant output flow, the
fracture fluid output flow and a motive fluid flow, the suction
chamber configured to output a fluid mixture to a mixing chamber;
and an expansion feature coupled to the mixing chamber and
configured to expand the fluid mixture therein for delivery to a
downstream component.
19. The apparatus of claim 12, wherein the high pressure
differential solids feeder assembly is rotary positive displacement
pump assembly coupled to the proppant storage vessel, the rotary
positive displacement pump assembly comprising: a pump body,
including a feed inlet at a first end and a discharge point at a
second end; and a feed mechanism disposed within the pump body and
configured to move the proppant material from the feed inlet to the
discharge point while increasing a pressure of the proppant
material from an ambient pressure to the mixing pressure.
20. A method of preparing and delivering a fluid mixture,
comprising: providing a continuous proppant output flow at ambient
pressure into a high pressure differential solids feeder assembly
configured to output a continuous pressurized proppant output flow
of a sufficient mass to achieve continuous operation of an
apparatus in an uninterrupted episode for an individual fracture
stage, wherein the continuous pressurized proppant output flow is
output at a mixing pressure, wherein the mixing pressure is greater
than the ambient pressure; inputting the continuous pressurized
proppant output flow and a continuous pressurized fracture fluid
output flow at the mixing pressure and of a sufficient volume to
achieve continuous operation of the apparatus in an uninterrupted
episode for an individual fracture stage, into a pressurized mixing
apparatus; and mixing the continuous pressurized proppant output
flow and the continuous pressurized fracturing fluid output flow
therein the pressurized mixing apparatus and outputting a
continuous pressurized flow of a fluid mixture of proppant and
fracturing fluid of a sufficient volume and mass to achieve
continuous operation of the apparatus in an uninterrupted episode
for the individual fracture stage, wherein the continuous flow of
the pressurized fluid mixture of proppant and fracturing fluid is
output at or above the mixing pressure.
21. The method of delivering a fluid mixture of claim 20, further
comprising: providing an input of a proppant material at ambient
pressure to a proppant storage vessel, the proppant storage vessel
configured to output the continuous proppant output flow at ambient
pressure; and providing an input of a fracture fluid at a mixing
pressure to a fracture fluid storage vessel, the fracture fluid
storage vessel configured to output the continuous pressurized
fracture fluid output flow at the mixing pressure.
22. The method of delivering a fluid mixture of claim 20, further
comprising: increasing the pressure of the continuous flow of the
pressurized fluid mixture of proppant and fracturing fluid in a
pump to output a continuous pressurized flow of an increased
pressure fluid mixture; and delivering the continuous pressurized
flow of an increased pressure fluid mixture to one or more
downstream components.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 13/689,873, filed Nov. 30, 2012 and is herein
incorporated in its entirety by reference.
BACKGROUND
[0002] Embodiments disclosed herein relate generally to an
apparatus and method of delivering a fluid mixture (i.e., slurry)
into a wellbore in an uninterrupted episode for each fracture stage
design.
[0003] Hydraulic stimulation or fracturing, commonly known as
hydrofracking, or simply fracturing, is a technique used to release
petroleum, natural gas or other substances for extraction from
underground reservoir rock formations. A wellbore is drilled into
the reservoir rock formation, and a treatment fluid is pumped which
causes fractures and allows for the release of trapped substances
produced from these subterranean natural reservoirs. Current
wellbore fracturing systems utilize a process wherein a slurry of a
fracturing fluid and a proppant (e.g. sand) is created and then
pumped into the well at high pressure. When water-based fracturing
fluids are used, the proppant, water and appropriate chemicals can
be mixed at atmospheric pressure and then pumped up to a higher
pressure for injection into the well.
[0004] This type of hydraulic stimulation, utilizing water-based
fracturing fluids, is usually undertaken in multiple fracture
stages or episodes. Stimulation of each individual fracture stage
utilizes a specific fluid volume and proppant mass per stage and,
due to the ability to operate and hold these materials under
ambient conditions, each fracture stage is able to be conducted in
one uninterrupted episode. Subsequent to completion of one fracture
stage, a subsequent fracture stage is commenced utilizing another
specific fluid volume and proppant mass to comprise the slurry, and
the process repeats.
[0005] At present, the desire in the industry is to stimulate using
fluids other than water, and more specifically liquefied or dense
phase supercritical gases, but maintaining the same fluid volumes
and proppant mass per fracture stage that is used for today's known
water stimulation methods. With the use of these alternate fluids,
the stimulation of each individual fracture stage is still
desirably sought to be accomplished in an uninterrupted episode for
each fracture stage. However, when fluids other than water (e.g.
liquid CO.sub.2 or liquid propane) are used as the fracturing
fluid, these fluids must be kept at a sufficient pressure
throughout the hydraulic fracturing system to avoid undesired
vaporization. As a result, the blending of these fracturing fluids
with proppant, chemicals, etc., to form the fracturing slurry, must
also be accomplished while the fluids are kept under a sufficiently
high pressure. Current pressurized blenders, or mixing apparatus
exist, for this purpose but with limitations.
[0006] Known pressurized blenders capable of blending these
vaporizing fracturing fluids with the proppant at a suitably high
pressure typically utilize a pressurized proppant storage vessel to
feed and meter the proppant into the pressurized fracturing fluid.
These known pressurized blenders require pre-loading with the
entire desired mass of proppant to be utilized during a given
fracture stage. After loading, the entire mass of proppant is
maintained under pressure within the blender. The pressurized
proppant storage vessels are typically single lock hopper
configurations having a capacity in the range of 20-40 tons of
proppant (e.g., sand). However, typical fracture stage designs
employ 125,000-250,000 lbs. or more of proppant for each stage of
fracturing. Due to volume limitations, a single known pressurized
lock hopper and pressurized blender assembly would only able to
pump a fraction of the complete fracture stage design. To provide
the required large proppant mass, multiple lock hopper
configurations may be utilized to deliver the desired fracture
stage design with proppant and additional fracturing fluids.
[0007] In addition, the limited volume capacity of known
pressurized proppant storage vessel systems provides for limited
amounts of proppant to be blended with the fracturing fluid. If the
fracturing design requires more sand, then multiple pressurized
proppant storage vessels must be used. This adds to the complexity
and capital expenditures of the fracturing system. In addition,
known pressurized blenders require an undesirably long elapsed time
to reload them with proppant for the next fracture stage. In some
instances, some pressurized blender operations require the blender
unit be moved off-site to another location for the purpose of
reloading with proppant, also requiring an undesirably long time
and potentially adding to the truck traffic associated with
fracturing operations. In many instances, the limited capacity
requires specialized logistics and on-pad (or off-pad) proppant
handling equipment to be used in conjunction with the pressurized
proppant storage vessel system.
[0008] Accordingly, there is a need for an improved pumping system
and method for delivering the alternate fracturing fluids (e.g.,
liquid CO.sub.2 or liquid propane), and more particularly a
fracturing slurry, into a wellbore that will enable the blending
and pumping of essentially unlimited quantities on an uninterrupted
basis of proppant and alternate fracturing fluid to form the fluid
mixture. The ability to deliver unlimited quantities will provide
for continuous operation of the pressurized blender and sand
feeding equipment in an uninterrupted episode throughout each
fracture stage, maintain the same desired total fluid volume and
proppant mass for each individual fracture stage in each
uninterrupted episode, enable fracture plans to be based upon
reservoir stimulation requirements without imposing equipment
constraints, and therefore providing overall a more efficient
hydraulic fracturing system.
BRIEF SUMMARY
[0009] These and other shortcomings of the prior art are addressed
by the present disclosure, which provides an apparatus and method
of preparing and delivering a fluid mixture using direct proppant
injection to a pressurized mixing apparatus.
[0010] In accordance with an embodiment, provided is an apparatus
for preparing and delivering a fluid mixture. The apparatus
includes a high pressure differential solids feeder assembly
coupled to a proppant storage vessel at an ambient pressure and a
pressurized mixing apparatus coupled to the high pressure
differential solids feeder assembly. The high pressure differential
solids feeder assembly includes a proppant inlet in fluidic
communication with a proppant flow at the ambient pressure. The
high pressure differential solids feeder assembly is configured to
output a continuous pressurized proppant output flow of a
sufficient mass to achieve continuous operation of the apparatus in
an uninterrupted episode for an individual fracture stage. The
continuous pressurized proppant output flow is output at a mixing
pressure, wherein the mixing pressure is greater than the ambient
pressure. The pressurized mixing apparatus is coupled to the high
pressure differential solids feeder assembly. The pressurized
mixing apparatus includes at least one inlet in fluidic
communication with the continuous pressurized proppant output flow
and a continuous pressurized fracturing fluid flow. The pressurized
mixing apparatus is configured to mix the continuous pressurized
proppant output flow and the continuous pressurized fracturing
fluid flow therein and output a continuous flow of a pressurized
fluid mixture of proppant and fracturing fluid of a sufficient
volume and mass to achieve continuous operation of the apparatus in
an uninterrupted episode for the individual fracture stage. The
continuous flow of the pressurized fluid mixture of proppant and
fracturing fluid is output at or above the mixing pressure.
[0011] In accordance with another embodiment, provided is an
apparatus for preparing and delivering a fluid mixture. The
apparatus includes a proppant storage vessel, a high pressure
differential solids feeder assembly, a fracturing fluid storage
vessel, a pressurized mixing apparatus and a pump assembly. The
proppant storage vessel is configured to contain therein a proppant
material and output a proppant output flow at ambient pressure. The
high pressure differential solids feeder assembly is coupled to the
proppant storage vessel. The high pressure differential solids
feeder assembly includes a proppant inlet in fluidic communication
with the proppant output flow. The high pressure differential
solids feeder assembly is configured to output a continuous
pressurized proppant output flow of a sufficient mass to achieve
continuous operation of the apparatus in an uninterrupted episode
for an individual fracture stage. The continuous pressurized
proppant output flow is output at a mixing pressure, wherein the
mixing pressure is greater than the ambient pressure. The
fracturing fluid storage vessel is configured to contain therein a
fracturing fluid and output a continuous pressurized fracturing
fluid output flow at a mixing pressure, wherein the fracture mixing
pressure is greater than the ambient pressure. The pressurized
mixing apparatus is coupled to the high pressure differential
solids feeder assembly. The pressurized mixing apparatus including
at least one inlet in fluidic communication with the continuous
pressurized proppant output flow and the continuous pressurized
fracturing fluid flow. The pressurized mixing apparatus is
configured to mix the continuous pressurized proppant output flow
and the continuous pressurized fracturing fluid flow therein and
output a continuous flow of a pressurized fluid mixture of proppant
and fracturing fluid of a sufficient volume and mass to achieve
continuous operation of the apparatus in an uninterrupted episode
for the individual fracture stage. The continuous flow of the
pressurized fluid mixture of proppant and fracturing fluid is
output at or above the mixing pressure. The pump assembly is
coupled to the pressurized mixing chamber and configured to deliver
the pressurized fluid mixture therein to a downstream component at
an injection pressure, wherein the injection pressure is greater
than the mixing pressure.
[0012] In accordance with yet another embodiment, provided is a
method of preparing and delivering a fluid mixture. The method
including providing a continuous proppant output flow at ambient
pressure into a high pressure differential solids feeder assembly
configured to output a continuous pressurized proppant output flow
of a sufficient mass to achieve continuous operation of the
apparatus in an uninterrupted episode for an individual fracture
stage, wherein the continuous pressurized proppant output flow is
output at a mixing pressure, wherein the mixing pressure is greater
than the ambient pressure; inputting the continuous pressurized
proppant output flow and a continuous pressurized fracture fluid
output flow at the mixing pressure and of a sufficient volume to
achieve continuous operation of the apparatus in an uninterrupted
episode for an individual fracture stage, into a pressurized mixing
apparatus; and mixing the continuous pressurized proppant output
flow and the continuous pressurized fracturing fluid output flow
therein the pressurized mixing apparatus and outputting a
continuous pressurized flow of a fluid mixture of proppant and
fracturing fluid of a sufficient volume and mass to achieve
continuous operation of the apparatus in an uninterrupted episode
for the individual fracture stage, wherein the continuous flow of
the pressurized fluid mixture of proppant and fracturing fluid is
output at or above the mixing pressure.
[0013] Other objects and advantages of the present disclosure will
become apparent upon reading the following detailed description and
the appended claims with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE FIGURES
[0014] The above and other features, aspects, and advantages of the
present disclosure will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein
[0015] FIG. 1 is a schematic diagram of an apparatus for delivering
a fluid mixture using a high pressure differential solids feeder
assembly for direct proppant injection to a pressurized mixing
apparatus constructed in accordance with an embodiment;
[0016] FIG. 2 is a schematic diagram of a portion of the apparatus
of FIG. 1 including a feeder assembly and pressurized mixing
apparatus constructed in accordance with an embodiment;
[0017] FIG. 3 is a schematic diagram of an apparatus for delivering
a fluid mixture using a Continuous solid feed pump assembly for
direct proppant injection to a pressurized mixing apparatus
constructed in accordance with another embodiment;
[0018] FIG. 4 is a schematic diagram of an apparatus for delivering
a fluid mixture using a eductor pump assembly direct proppant
injection to a pressurized mixing apparatus constructed in
accordance with still another embodiment;
[0019] FIG. 5 is a schematic diagram of an apparatus for delivering
a fluid mixture using a pressurized rotary positive displacement
pump assembly for direct proppant injection to a pressurized mixing
apparatus constructed in accordance with still another embodiment;
and
[0020] FIG. 6 is a schematic block diagram of a method of
delivering a fluid mixture using a direct proppant injection to a
pressurized mixing apparatus constructed in accordance with still
another embodiment.
DETAILED DESCRIPTION
[0021] This disclosure will be described for the purposes of
illustration only in connection with certain embodiments; however,
it is to be understood that other objects and advantages of the
present disclosure will be made apparent by the following
description of the drawings according to the disclosure. While
preferred embodiments are disclosed, they are not intended to be
limiting. Rather, the general principles set forth herein are
considered to be merely illustrative of the scope of the present
disclosure and it is to be further understood that numerous changes
may be made without straying from the scope of the present
disclosure.
[0022] Preferred embodiments of the present disclosure are
illustrated in the figures with like numerals being used to refer
to like and corresponding parts of the various drawings. It is also
understood that terms such as "top", "bottom", "outward", "inward",
and the like are words of convenience and are not to be construed
as limiting terms. It is to be noted that the terms "first,"
"second," and the like, as used herein do not denote any order,
quantity, or importance, but rather are used to distinguish one
element from another. The terms "a" and "an" do not denote a
limitation of quantity, but rather denote the presence of at least
one of the referenced item. The modifier "about" used in connection
with a quantity is inclusive of the stated value and has the
meaning dictated by the context (e.g., includes the degree of error
associated with measurement of the particular quantity).
[0023] As used herein, the process of forming of a fluid mixture
includes mixing a fluid with a powdered or particulate material,
such as proppant, a powdered dissolvable or a hydratable additive
(prior to hydration). The fluids are handled as continuous fluid
streams over an uninterrupted episode for each fracture stage.
[0024] Referring to the drawings wherein, as previously stated,
identical reference numerals denote the same elements throughout
the various views, FIG. 1 depicts in a simplified block diagram,
elements of an apparatus 100 for preparing and delivering a
continuous fluid mixture (slurry) of solids (proppant) and
liquefied gas, including direct proppant injection to a pressurized
blender, or mixing apparatus, including sufficient fluid volume and
proppant mass so as to achieve an uninterrupted episode for each
individual fracture stage to achieve the desired fracture stage
design, according to an embodiment.
[0025] The apparatus 100 includes a proppant storage vessel 102
coupled to a high pressure differential solids feeder assembly 104
at an inlet 106 of the high pressure differential solids feeder
assembly 104. The proppant storage vessel 102 includes an outlet
108 configured in fluidic communication with the inlet 106 of the
high pressure differential solids feeder assembly 104. The proppant
storage vessel 102 is configured as a traditional unpressurized
storage type vessel and includes a body 110 configured to hold a
proppant material 112 therein at atmospheric pressure, also
referred to herein as ambient pressure. In an embodiment, the
proppant storage vessel 102 may be configured including an open top
and configured to hold the proppant material 112 therein at
atmospheric pressure. In an embodiment, the proppant storage vessel
may be configured including a closed top and configured to hold the
proppant material 112 therein at atmospheric pressure. The proppant
storage vessel 102 may further include a proppant material inlet
114 coupled to a proppant material loading device 116 and a source
of proppant material (not shown). In an embodiment, the proppant
material 112 may be comprised of sand, ceramic proppant, a mixture
thereof or other material utilized as proppant in hydraulic
fracturing operations. The proppant storage vessel 102 provides
adequate storage and loading capabilities to allow for a supply of
proppant material 112 to the high pressure differential solids
feeder assembly 104 sufficient to achieve continuous operation of
the apparatus 100 in an uninterrupted episode for an individual
fracture stage.
[0026] During operation, the proppant storage vessel 102 may be
loaded by the material loading device 116, such as a screw auger,
conveyor, or any other means configured to move the proppant
material 112 from a proppant supply source (not shown) to the
proppant storage vessel 102. Alternate means for providing the
proppant material 112 to the proppant storage vessel 102 are
anticipated herein. The proppant storage vessel 102 is configured
to hold the proppant material 112 therein at atmospheric pressure
and thus enables loading/recharging during operation of the
remaining system components.
[0027] The high pressure differential solids feeder assembly 104
includes a pump assembly capable of receiving a continuous proppant
output flow 118 at atmospheric pressure via outlet 108 of the
proppant storage vessel 102 and the inlet 106 of the high pressure
differential solids feeder assembly 104. The high pressure
differential solids feeder assembly 104 is further configured to
provide at an outlet 120, a continuous pressurized proppant output
flow 122 at a mixing pressure, wherein the continuous pressurized
proppant output flow 122 is of a sufficient mass flow to provide
continuous operation of the apparatus 100 in an uninterrupted
episode for each individual fracture stage. The mixing pressure at
which the continuous pressurized proppant output flow 122 is
discharged is greater than the ambient pressure. In an embodiment,
the mixing pressure is in a range of about 50 psi to 400 psi, and
preferably at a pressure of approximately 300 psi.
[0028] A pressurized blender, or mixing apparatus, 124 is
configured to receive the continuous pressurized proppant output
flow 122 via a proppant inlet 126. A pressurized fracturing fluid
storage vessel 128 is provided in fluidic communication via an
outlet 130 with a fracturing fluid inlet 132 of the pressurized
mixing apparatus 124. The fracturing fluid storage vessel 128 is
configured for storage of a fracturing fluid 134 at a required
temperature and storage pressure, and more particularly at or above
the mixing pressure. The pressurized mixing apparatus 124 is
configured to receive a continuous pressurized fracturing fluid
output flow 136 at the mixing pressure via the inlet 132, wherein
the continuous pressurized fracturing fluid output flow 136 is of a
sufficient volume to provide continuous operation of the apparatus
100 in an uninterrupted episode for each individual fracture
stage.
[0029] During operation, the continuous pressurized proppant output
flow 122 and the continuous pressurized fracturing fluid output
flow 136 are blended, or mixed, within the pressurized mixing
apparatus 124 at the mixing pressure. Subsequent to mixing, the
pressurized mixing apparatus 124 provides a continuous fluid
mixture output flow 138, previously referred to herein as a slurry,
to a high pressure fracturing fluid (slurry) pump assembly 142, via
an outlet 140, wherein the continuous fluid mixture (slurry) output
flow 138 is sufficient to provide continuous operation of the
apparatus 100 in an uninterrupted episode for each individual
fracture stage. In alternate embodiments, a fracture fluid (slurry)
booster pump 141 may be provided inline between the mixing
apparatus 124 and the high pressure fracturing fluid (slurry) pump
assembly 142, or alternatively provided as part of the
functionality of the high pressure fracturing fluid (slurry) pump
assembly 142. The continuous fluid mixture (slurry) output flow 138
is output at the mixing pressure. The continuous fluid mixture
(slurry) output flow 138 is received via a fluid mixture inlet 144
of the high pressure pump assembly 142. The high pressure
fracturing fluid (slurry) pump assembly 142 is configured to
deliver the continuous fluid mixture (slurry) output flow 138
received therein to a downstream component 146 at an injection
pressure, wherein the injection pressure is greater than the mixing
pressure. More specifically, in an embodiment, the high pressure
fracturing fluid (slurry) pump assembly 142 is configured to
deliver a continuous high pressure fluid mixture (slurry) output
flow 148 via an outlet 150 of the high pressure fracturing fluid
(slurry) pump assembly 142 to an inlet 152 of the downstream
component 146, such as a well head 154, wherein the continuous high
pressure fluid mixture (slurry) output flow 148 is of sufficient
volume and mass to provide continuous operation of the apparatus
100 in an uninterrupted episode for each individual fracture
stage.
[0030] Referring more specifically to FIG. 2, illustrated is a
portion of the apparatus 100 of FIG. 1 as indicated by dotted line
in FIG. 1. More particularly, illustrated in FIG. 2 are the high
pressure differential solids feeder assembly 104 and the
pressurized mixing apparatus 124. The inclusion of the high
pressure differential solids feeder assembly 104 in apparatus 100
provides unlimited amounts of the proppant material 112 to be
continuously blended with the pressurized fracturing fluid 134,
using conventional sand logistics and on-pad handling equipment.
The high pressure differential solids feeder assembly 104 is
capable of operating continuously in uninterrupted episodes
throughout each fracture stage, in contrast to semi-batch operating
modes of the state of the art lock hoppers, whereby the proppant
must be batch pressurized in a mixing apparatus with multiple lock
hopper cycles or multiple lock hopper configurations required to
deliver sufficient output flow for similar desired fracture stage
designs.
[0031] As illustrated in FIG. 2, the high pressure differential
solids feeder assembly 104 separates the low pressure inlet, and
more particularly the inlet 106 from the high pressure outlet, and
more particularly the outlet 120. This separation enables transport
of the bulk solids (proppant) from the low pressure inlet 106 to
the high pressure discharge area 120 on a continuous, uninterrupted
basis while simultaneously preventing a flow of the pressurized
fracturing fluid 134, via the fracturing fluid output flow 136,
back to the inlet 106. In contrast to known lock hopper designs
that may include a valve configured to intermittently open and
close to create separation of pressure zones, the high pressure
differential solids feeder assembly 104 provides for an
uninterrupted solids flow at both the inlet 106 and the outlet 120,
simultaneously. In an embodiment, while some degree of high
pressure fluid backflow may occur through the high pressure
differential solids feeder assembly 104, the device 104 is
configured to actively manage such back flow (e.g., active
venting).
[0032] In an embodiment, the high pressure differential solids
feeder assembly 104 may be a continuous solid feed pump assembly,
such as a Posimetric.RTM. pump assembly, (described presently) that
employs positive-displacement action to provide precise flow
control and positive metering of the unpressurized proppant
material output flow 118 into the pressurized mixing apparatus 124,
a screw auger, conveyor, or any other similar means (described
presently) configured to move the unpressurized proppant material
output flow 118 into the pressurized mixing apparatus 124, an
eductor pump assembly (described presently) that employs the
Venturi effect to convert pressure energy of a motive fluid to
velocity energy to feed the unpressurized proppant material output
flow 118 into the pressurized mixing apparatus 124, or a
rotary-type pump (i.e., a rotary valve) that employs
positive-displacement action to feed the unpressurized proppant
material output flow 118 into the pressurized mixing apparatus
124.
[0033] In an embodiment the pressurized mixing apparatus 140 is
configured as a tank that provides for mixing of contents therein
in response to agitation or in response to static mixing utilizing
plates and/or mixer elements that provide for mixing in response to
turbulence and/or mixing of a plurality of flow paths generated in
the flow.
[0034] In an embodiment, the integration of the high pressure
differential solids feeder assembly 104 with the pressurized mixing
apparatus 140 may include coupling the outlet 120 of the high
pressure differential solids feeder assembly 104 to a gas headspace
(not shown) of the pressurized mixer apparatus 140. In addition, in
an embodiment, the pressurized mixer apparatus 140 may employ a
small retention volume so as to allow for faster change-overs
between proppant sizes and types.
[0035] Further embodiments of an apparatus for delivering a
pressurized fluid using continuous direct injection of a proppant
at ambient pressure into a pressurized mixing apparatus, of a
sufficient volume and mass to provide continuous operation of the
apparatus 100 in an uninterrupted episode for each individual
fracture stage, are illustrated in FIGS. 3-5. More particularly,
illustrated are alternate embodiments of the high pressure
differential solids feeder assembly 104 as described in FIGS. 1 and
2. Each of the embodiments of FIGS. 3-5 addresses the direct
delivery of a dry proppant material, such as proppant material 112
of FIG. 1, to a pump assembly for pressurization and subsequent
mixing with the fracturing fluid 134 in a pressurized mixing
apparatus 124. Utilizing a dry proppant material obviates the need
for additional fluid for wetting, thereby simplifying the process
and required equipment and removing costly and potentially
flammable (e.g., hydrocarbon) wetting agent(s). Each of the
embodiments of FIGS. 3-5 describes a pump assembly that may be
utilized for the high pressure differential solids feeder assembly
104, as described in FIGS. 1 and 2. Accordingly, like numbers are
used to identify like elements throughout the described embodiments
and in an effort to provide a concise description of these
embodiments, like features and elements previously described will
not be further described.
[0036] Referring more specifically to FIG. 3, illustrated is an
embodiment of an apparatus for delivering a continuous,
uninterrupted fluid mixture, generally referenced 200. The
apparatus 200 includes a proppant storage vessel 102 configured to
contain therein an unpressurized proppant material 112 and output a
continuous unpressurized proppant output flow 118 at ambient
pressure. A high pressure differential solids feeder assembly 104
is provided and coupled to the proppant storage vessel 102. The
high pressure differential solids feeder assembly 104 includes a
proppant inlet 106 in fluidic communication with the unpressurized
proppant storage vessel proppant output flow 118. In this
particular embodiment, the high pressure differential solids feeder
assembly 104 is a continuous solid feed pump assembly 202. The
continuous solid feed pump assembly 202 employs
positive-displacement action to feed the unpressurized proppant
material output flow 118 without the need for a pressurizing fluid,
into the pressurized mixing apparatus as a continuous flow
sufficient to provide continuous operation of the apparatus 200 in
an uninterrupted episode for each individual fracture stage. In
this particular embodiment, the continuous solid feed pump assembly
202 does not employ screws, augers, belts or vibratory trays to
convey the unpressurized proppant material output flow 118 and in
contrast employs at least one vertical rotating spool 204 disposed
within a pump body 208 to move the proppant material 112 therein.
The continuous proppant output flow 118 is initially input at an
input 106 that is coupled to the pump body 208. As the continuous
proppant output flow 118 enters and fills the pump assembly 202,
and more particularly the pump body 208, from above, the material
locks itself firmly into the confines of the rotating spool 204
contained therein, which carries it through an arc of approximately
180.degree.. More particularly, the continuous proppant output flow
118 is rotated within the rotating spool 204, housed within the
pump body 208, where it becomes "locked up" or compacted so as to
act as a solid mass, and discharged via an output duct 210 at the
outlet 120 as a continuous pressurized proppant output flow 122 of
sufficient mass to provide continuous operation of the apparatus
200 in an uninterrupted episode for each individual fracture stage.
While within the pump body 208, the proppant material 118 acts as a
solid mass and a seal against the high pressure outlet 120. At the
time of discharge via the outlet 120, the continuous pressurized
proppant material output flow 122 is output at an increased
pressure, and more particularly at a mixing pressure that is higher
than ambient pressure.
[0037] In a preferred embodiment, the continuous solid feed pump
assembly 202 is configured as a rotary displacement pump assembly
203, and includes a consolidation section 212, a rotating section
214 and a discharge section 216. During operation, the
unpressurized proppant material output flow 118 enters the pump
assembly 202 and becomes consolidated as the individual proppant
material particles settle and come into contact with each other as
well as the sidewalls defining the pump body 208, the particles
become compacted and act as a solid mass and form a seal against
the high pressure outlet environment. As the unpressurized proppant
material output flow 118 rotates in the rotating spool 204 and pump
body 208, the pressure of the proppant material output flow 118 is
increased, forming the continuous pressurized proppant output flow
122. Discharge of the continuous pressurized proppant output flow
122 at the increased mixing pressure occurs upon rotating of the
rotating spool 204 to the outlet 120. Exemplary pump assemblies are
described in commonly assigned U.S. Pat. No. 8,006,827, D. Aldred
et al., "Transporting Particulate Material", issued Aug. 3, 2011,
which is incorporated by reference herein in its entirety.
[0038] The continuous solid feed pump assembly 202 is configured to
output the continuous pressurized proppant output flow 122 at the
mixing pressure, wherein the mixing pressure is greater than the
ambient pressure. The apparatus 200 further includes a fracturing
fluid storage vessel 128 configured to contain therein a fracturing
fluid 134 and output a continuous pressurized fracturing fluid
output flow 136 at or above the mixing pressure, of a sufficient
volume to provide continuous operation of the apparatus 200 in an
uninterrupted episode for each individual fracture stage. A
pressurized blender, or mixing apparatus, 124 is coupled to the
continuous solid feed pump assembly 202 to receive the discharged
continuous pressurized proppant output flow 122. The pressurized
mixing apparatus 124 is additionally coupled to the pressurized
fracturing fluid storage vessel 128 to receive the discharged
continuous fracturing fluid output flow 136 therefrom. The mixing
apparatus 124 is configured to mix the continuous pressurized
proppant output flow 122 and the continuous pressurized fracturing
fluid output flow 136 therein and output a continuous output of a
fluid mixture (slurry) 138 of proppant and fracturing fluid, at the
mixing pressure, and of a sufficient volume and mass to provide
continuous operation of the apparatus 200 in an uninterrupted
episode for each individual fracture stage to deliver the proppant
mass and fluid volume desired by the fracture stage design. A
fracturing fluid (slurry) booster pump 141 and a high pressure
fracturing fluid (slurry) pump assembly 142 are coupled to the
mixing apparatus 124 and configured to receive the continuous
output of a fluid mixture (slurry) 138 and deliver a continuous
flow of a high pressure fluid mixture (slurry) 148 therein to a
downstream component 146 at an injection pressure and in an amount
sufficient to provide continuous operation of the apparatus 200 in
an uninterrupted episode for each individual fracture stage. The
injection pressure of the continuous flow of a high pressure fluid
mixture (slurry) 148 is at or greater than the mixing pressure.
[0039] Referring more specifically to FIG. 4, illustrated is
another embodiment of an apparatus 300 for delivering a continuous
flow of a high pressure fluid mixture (slurry) of a sufficient
volume and mass to provide continuous operation of the apparatus
300 in an uninterrupted episode for each individual fracture stage
as desired by the fracture stage design. The apparatus 300 includes
a proppant storage vessel 102 configured to contain therein a
proppant material 112 and output a continuous proppant output flow
118 at ambient pressure. The apparatus 300 further includes a
fracturing fluid storage vessel 128 configured to contain therein a
pressurized fracturing fluid 134 and output a continuous
pressurized fracturing fluid output flow 136 at or above a mixing
pressure, wherein the mixing pressure is greater than the ambient
pressure as previously described. A high pressure differential
solids feeder assembly 104 is provided and coupled to the proppant
storage vessel 102 and the fracturing fluid storage vessel 128. The
high pressure differential solids feeder assembly 104 includes a
proppant inlet 106 in fluidic communication with the proppant
storage vessel continuous proppant output flow 118 and a fracture
fluid inlet 324 in fluidic communication with at least a portion of
the continuous pressurized fracturing fluid output flow 136. In
this particular embodiment, the high pressure differential solids
feeder assembly 104 is an eductor pump assembly 302. During
operation, the eductor pump assembly 302 employs the Venturi effect
of a converging-diverging nozzle to convert the pressure energy of
a motive fluid, and more particularly a portion of the continuous
fracturing fluid output flow 136, to velocity energy to feed the
proppant material 112. Similar to the previously described
continuous solid feed pump assembly 202, the eductor pump assembly
302 does not employ screws, augers, belts or vibratory trays to
convey the proppant material 112 within the pump assembly toward
the downstream components.
[0040] As illustrated in FIG. 4, the continuous proppant output
flow 118 is initially input into the eductor pump assembly 302 via
an input duct 306 that is coupled to a pump body 308. The input of
the continuous proppant output flow 118 may be metered by a valve
mechanism (not shown) disposed in the input duct 306. In an
embodiment, the eductor pump assembly 302 further includes a first
converging nozzle 310, a second converging nozzle 312, a mixing
chamber 314 and a diffuser, or expansion feature, 316.
[0041] In an embodiment, the eductor pump assembly 302 includes the
eductor body 308, and more particularly a suction chamber 318 that
is driven by the motive fluid, and more particularly at least a
portion of the continuous fracturing fluid output flow 136 utilized
as a motive flow. In an embodiment, at least a portion of the
continuous fracturing fluid output flow 136 is input directly into
the pressurized mixing apparatus 124. The continuous fracturing
fluid output flow 136 is accelerated through the first converging
nozzle 310. As with traditional eductors, accelerating a higher
pressure fluid through the first converging nozzle 310 drops the
static pressure of a motive flow exiting through the first
converging nozzle 310, while simultaneously decreasing the static
pressure within the suction chamber 318. The lower suction pressure
in the suction chamber 318 draws in the continuous proppant output
flow 118, as a suction flow via the inlet port 106 of the eductor
pump assembly 302. Subsequently, a continuous flow of a fluid
mixture 320 of a sufficient volume and mass to provide continuous
operation of the apparatus 300 in an uninterrupted episode for each
individual fracture stage, comprised of a combination of the
continuous proppant output flow 118 and the continuous pressurized
fracturing fluid output flow 136, is delivered to the second
converging nozzle 312 prior to reaching the mixing chamber 314. The
fluid mixture 320, comprised of the continuous proppant output flow
118 and the continuous pressurized fracturing fluid output flow
136, is further mixed within the pressurized mixing chamber 314 as
the stratifications between the two fluids are allowed to settle
out and as the turbulent fluid structure is reduced. The continuous
flow of the fluid mixture 320 exiting the mixing chamber 314 is
expanded in the expansion feature 316, prior to being delivered to
the downstream components that may ultimately be in fluidic
communication with a wellhead. The expansion feature 316 provides
an expansion of the fluid mixture 320 and provides a decrease in
the velocity of the fluid mixture 320 and recovery of the pressure
of the fluid mixture 320 allowing the fluid to be delivered to a
pressurized mixing apparatus 124 in a continuous flow, at the
mixing pressure, and a sufficient volume and mass to provide
continuous operation of the apparatus 300 in an uninterrupted
episode for each individual fracture stage to deliver the proppant
mass & fluid volume desired by the fracture stage design.
[0042] During operation of the apparatus 300, including the eductor
pump assembly 302, the eductor pump assembly 302 is placed in
operation by pressurizing the suction chamber 318. Subsequent to
the appropriate pressure condition being reached, an optional valve
mechanism, or gate, 322, disposed between the proppant storage
vessel 102 and the inlet port 106 may be opened to allow the
proppant storage vessel 102 contents to enter the eductor pump
assembly 302, and more particularly the suction chamber 318. The
suction chamber 318 draws in the continuous proppant output flow
118, including the proppant material 112, as the suction flow, and
subsequently mixes with the motive flow, and more particularly, at
least a portion of the pressurized fracturing fluid output flow
136. Operation of the apparatus is continuous and uninterrupted
with a continuous flow of the proppant output flow 118 and the
fracturing fluid output flow 136 in a volume sufficient to provide
continuous operation of the apparatus 300 in an uninterrupted
episode for each individual fracture stage as desired by the
fracture stage plan.
[0043] It should be noted that valve mechanism 322 is optional,
being required in an application where the desire is to allow the
eductor pump assembly 302 to remain at full pressure. As valves in
the direct path of the proppant output flow 118, and more
particularly proppant material 112, it will be subject to a harsh
abrasive environment, it is realized that valve mechanism 322 will
be subject to higher wear rates. As such, an embodiment eliminating
the valve mechanism 322 is anticipated.
[0044] The eductor pump assembly 302 is configured to output a
continuous pressurized proppant output flow 122 of a sufficient
mass and a continuous pressurized fracturing fluid output flow 136
of a sufficient volume to provide continuous operation of the
apparatus 300 in an uninterrupted episode for each individual
fracture stage. The apparatus 300 further includes the pressurized
blender, or pressurized mixing apparatus, 124 coupled to the
eductor pump assembly 302 to continuously receive the discharged
continuous pressurized proppant output flow 122 therefrom and the
continuous pressurized fracturing fluid output flow 136. The
pressurized mixing apparatus 124 is configured to mix the
continuous pressurized proppant output flow 122 and the continuous
pressurized fracturing fluid output flow 136 therein and output a
continuous pressurized fluid mixture (slurry) output flow 138 of
proppant and fracturing fluid at the mixing pressure. A fracturing
fluid booster pump 141 and a high pressure fracturing fluid
(slurry) pump assembly 142 are coupled to the mixing apparatus 124
and configured to deliver the continuous pressurized fluid mixture
(slurry) 138 therein to a downstream component 146 as a high
pressure fluid mixture (slurry) output flow 148 at an injection
pressure, wherein the injection pressure is greater than the mixing
pressure, and of a sufficient volume and mass to provide continuous
operation of the apparatus 300 in an uninterrupted episode for each
individual fracture stage to deliver the proppant mass & fluid
volume desired by the fracture stage plan.
[0045] Accordingly, the inclusion of the eductor pump assembly 302,
as described in apparatus 300, provides for use of at least a
portion of the continuous flow of pressured fracturing fluid 136 as
the motive fluid flow through the eductor pump assembly 302 to
convey the proppant 112 and more particularly the proppant output
flow 118 into the flowing motive fluid.
[0046] Referring now to FIG. 5, illustrated is another embodiment
of an apparatus for preparing and delivering a continuous fluid
mixture (slurry) of solids (proppant) and liquefied gas, generally
referenced 400. The apparatus 400 includes a proppant storage
vessel 102 configured to contain therein a proppant material 112
and output a continuous proppant output flow 118 at ambient
pressure. The apparatus 400 further includes a fracturing fluid
storage vessel 128 configured to contain therein a pressurized
fracturing fluid 134 and output a continuous pressurized fracturing
fluid output flow 136 at or above a mixing pressure, wherein the
mixing pressure is greater than the ambient pressure as previously
described. A high pressure differential solids feeder assembly 104
is provided and coupled to the proppant storage vessel 102 and the
fracturing fluid storage vessel 128. The high pressure differential
solids feeder assembly 104 includes a proppant inlet 106 in fluidic
communication with the continuous proppant storage vessel proppant
output flow 118. In this particular embodiment, the high pressure
differential solids feeder assembly 104 is a positive displacement
pump, and more particularly a rotary-type positive displacement
pump, such as an internal gear, screw, rotary valve, or auger type
pump assembly, referenced 402. The unique design of the positive
displacement pump 402 ensures that the proppant material 112 is
constantly present at a feed inlet 404, while the controlled
rotation of a feed mechanism 406 moves the proppant material 112,
and more particularly the continuous unpressurized proppant output
flow 118, from the ambient pressure feed inlet 404 to a pressurized
discharge point 408. In the illustrated embodiment, the feed
mechanism 406 comprises a screw mechanism 410 (a helical surface
surrounding a central cylindrical shaft) disposed inside a hollow
body 412.
[0047] As illustrated in FIG. 5, the continuous proppant output
flow 118 is initially input into the rotary-type positive
displacement pump 402 via the feed inlet 404. Similar to the
previous embodiment, the input of the continuous proppant output
flow 118 may be metered by an optional valve mechanism (not shown).
Similar to the continuous solid feed pump assembly 202 of FIG. 3,
the positive displacement pump assembly 402 employs
positive-displacement action to feed the proppant material 112 as a
free-flowing material with a uniform discharge in a linear
volumetric fashion. In contrast to the continuous solid feed pump
assembly 202 of FIG. 3, the positive displacement pump assembly 402
employs screws, augers, rotary valves, belts or vibratory trays to
convey the proppant material 112 therein. The continuous proppant
output flow 118 is initially input at the feed inlet 404 that is
coupled to the pump body 412. As the continuous proppant output
flow 118 enters and fills the pump assembly 402, and more
particularly the pump body 412, the material is carried by the feed
mechanism 406 contained therein, toward the discharge point 408.
The continuous ambient pressure proppant output flow 118 is rotated
within the feed mechanism 406, housed within the pump body 412 and
discharged via an output duct 414 at the discharge point 408 as a
continuous pressurized proppant output flow 122. At the time of
discharge via an outlet 120, the continuous proppant material
output flow 122 is output at an increased pressure, and more
particularly at a mixing pressure that is greater than the ambient
pressure and of a sufficient mass to provide continuous operation
of the apparatus 400 in an uninterrupted episode for each
individual fracture stage to deliver the proppant mass & fluid
volume desired by the fracture stage plan.
[0048] In a preferred embodiment, during operation, the proppant
material 112 enters the rotary-type positive displacement pump 402
at the feed inlet 404. As the proppant material 112 rotates in the
feed mechanism 410 and pump body 412, the pressure of the proppant
material 112 is increased. Discharge of the proppant material 112
at the increased mixing pressure occurs upon rotation of the feed
mechanism 406 relative to the outlet 120.
[0049] The apparatus 400 further includes a pressurized blender, or
mixing apparatus, 124 coupled to the rotary-type positive
displacement pump 402 to receive the discharged continuous
pressurized proppant output flow 122 therefrom and the continuous
pressurized fracturing fluid output flow 136. The mixing apparatus
124 is configured to mix the continuous pressurized proppant output
flow 122 and the continuous pressurized fracturing fluid output
flow 134 therein and output a continuous pressurized flow of a
fluid mixture (slurry) 138 of proppant material 112 and fracturing
fluid 134 at an increased pressure of a sufficient volume and mass
to provide continuous operation of the apparatus 400 in an
uninterrupted episode for each individual fracture stage as
required by the fracture stage design. A high pressure fracturing
fluid (slurry) pump assembly 142 coupled to the mixing chamber 124
is configured to receive the continuous pressurized flow of a fluid
mixture (slurry) 138 and deliver a continuous pressurized flow of a
high pressure fluid mixture (slurry) 148 to a downstream component
146 at an injection pressure, wherein the injection pressure is
greater than the mixing pressure, and of a sufficient volume and
mass to provide continuous operation of the apparatus 400 in an
uninterrupted episode for each individual fracture stage. In this
particular embodiment, a separate booster pump is not provided, and
in lieu of, boosting of the mixing pressure is provided as part of
the functionality of the high pressure fracturing fluid (slurry)
pump assembly 142.
[0050] FIG. 6 is a schematic block diagram of a method 500 of
delivering a fluid mixture using direct proppant injection to a
pressurized mixing apparatus including the high pressure
differential solids feeder assembly 100, 200, 300, 400 according to
an embodiment disclosed herein. Generally, the method involves
providing an input of a proppant material 112 to an ambient
pressure proppant storage vessel 102, and providing an input of a
pressurized fracturing fluid 134 to a fracture fluid storage vessel
128, at a step 502. Next in step 504, a continuous proppant output
flow 118 at ambient pressure from the proppant storage vessel 102
is input into a high pressure differential solids feeder assembly
104. As previously described, the high pressure differential solids
feeder assembly 104 may be configured as a positive displacement
pump assembly, and more particularly a continuous solid feed pump
assembly 202 (as best illustrated in FIG. 3), as an eductor pump
assembly 302 (as best illustrated in FIG. 4) or a rotary-type
positive displacement pump 402 (as best illustrated in FIG. 5).
Next in step 506, a continuous pressurized proppant output flow 122
and a continuous pressurized fracturing fluid output flow 136 are
input to a pressurized mixing apparatus 124. The pressurized mixing
apparatus 124 is configured to mix the continuous pressurized
proppant output flow 122 and the continuous pressurized fracturing
fluid output flow 136 therein and output a continuous pressurized
fluid mixture (slurry) output flow 138 of the proppant and
fracturing fluid at the mixing pressure, at step 508. The pressure
of the continuous pressurized fluid mixture (slurry) output flow
138 is next increased in a high pressure fracturing fluid (slurry)
pump assembly 142, at step 510. Subsequently a continuous high
pressure fluid mixture (slurry) 148 is delivered to one or more
downstream components 146, at a step 512, and ultimately may
include delivery to a well head.
[0051] The apparatus for delivering a fluid using direct proppant
injection, as disclosed herein, enables continuous operation of the
apparatus at a steady condition in an uninterrupted episode for
each individual fracture stage to deliver the proppant mass &
fluid volume desired by the fracture stage design. The apparatus by
providing continuous pressurized flows of proppant and fracturing
fluid into the mixing apparatus eliminates the stop-start operation
that must be performed when the volume being held is smaller than
the desired amount needed for each individual fracture stage
design. The apparatus removes the requirement to store all (or at
least a significant portion) of the proppant to be used for each
fracturing stage in a pressurized bulk proppant storage pressure
vessel, and instead allows use of existing proppant management
apparatus at ambient pressure such that an unlimited amount of
proppant can be blended online (as opposed to in batches) with the
pressurized fracturing fluid to deliver the proppant mass and fluid
volume desired by the fracture stage design.
[0052] Additional commercial advantages of the disclosed apparatus
are related to the current problem faced in unconventional gas
development and the requirement to mix/blend chemicals and a
proppant, namely sand with fracturing fluids (e.g., liquid
CO.sub.2, liquid propane gas) that require they always be contained
at a suitable mixing pressure to avoid vaporization of these
fracturing fluids. Accordingly, disclosed is an apparatus and
method of continuously preparing and delivering a fluid mixture of
solids (proppant) with liquefied gas using a high pressure
differential solids feeder assembly and direct proppant injection
into a pressurized mixing apparatus in such a way that a continuous
pressurized flow of proppant of a sufficient volume to provide
continuous operation of the apparatus in an uninterrupted episode
for each individual fracture stage can be provided without being
constrained by the total volume limits of the known lock hopper
based approaches. The disclosed apparatus provides a continuous
pressurized fluid mixture output flow of a sufficient volume and
mass to provide continuous operation of the apparatus in an
uninterrupted episode for each individual fracture stage to deliver
the proppant mass and fluid volume desired by the fracture stage
design.
[0053] The foregoing has described an apparatus and method of
preparing and delivering a fluid mixture (slurry) of solids
(proppant) and liquefied gas using direct injection of a proppant
into a pressurized mixing apparatus. While the present disclosure
has been described with respect to a limited number of embodiments,
those skilled in the art, having benefit of this disclosure, will
appreciate that other embodiments may be devised which do not
depart from the scope of the disclosure as described herein. While
the present disclosure has been described with reference to
exemplary embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the disclosure. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
present disclosure without departing from the essential scope
thereof. Therefore, it is intended that the present disclosure not
be limited to the particular embodiment disclosed as the best mode
contemplated for carrying out the disclosure. It is, therefore, to
be understood that the appended claims are intended to cover all
such modifications and changes as fall within the true spirit of
the disclosure.
* * * * *